1. Field of Invention
This invention relates to epoxide resin curing agents. More particularly, this invention to novolac based polyamines which may be used to cure polyepoxides in solvent based systems.
2. Prior Art
Ambient temperature curable epoxide resin systems have been known for many years. Predominate are the amine based systems such as the polyamido amines and the curing agents based upon polyalkylenepolyamines. However, many prior art relatively low temperature curing systems have been extremely slow to cure at these reduced temperatures--particularly temperatures which are witnessed during the winter months in the east and in northern latitudes. Thus the search has continued to discover epoxide resin curing agents which are operable at low temperatures but which, under these conditions, produce cured epoxide resin coatings which exhibit optimum cured state properties.
U.S. Pat. No. 4,116,900 discloses cathodic electro deposition resin systems prepared based upon polyepoxides, polyamines and monoepoxides. While the monoepoxide and polyamine are similar to the products used in this invention, the polyepoxide utilized in the '900 patent is quite different. Specifically in column 3, lines 47 to 68 there is no disclosure of the use of novolac type, highly branched, highly functional epoxy resins.
Likewise, U.S. Pat. No. 4,246,148 discloses an aqueous coating composition based upon a epoxy polyamine adduct end capped with monoepoxide. Again in the '148 patent it is made clear that highly functional, highly branched epoxide such as the novolac resin were not contemplated. Specifically in column 5 lines 10 to 20, a general formula is shown which clearly discloses a diepoxide, not a tri- or tetra-functional epoxide as contemplated by the applicant.
Thus it is the object of this invention to prepare curing agents which are useful at temperatures of less than about 30.degree. F.
Another object of this invention is to prepare epoxide resin curing agents which are useful in solvent based systems.
It is another object of this invention to prepare epoxide curing resin agents which provide optimum cured state properties for epoxy resins cured under ambient or less than ambient condition.
These and other objectives are obtained by preparing the epoxide resin curing agents of the instant invention.